Allow calling setFrameGeometry() while the client is being resized
Currently, if some script attempts to resize a window while it's being interactively resized, the corresponding change won't be propagated to the X server.
The main reason for that is that we don't want to configure the frame window, the wrapper window, and the client window twice. However, since Xcb::Window keeps track of the last configured geometry, we can adjust X11Client::updateServerGeometry() so it only configures windows that have mismatching geometry.
By doing so, the setFrameGeometry() function can be called by scripts even when the associated X11 window is being interactively resized.
Note that this bug doesn't affect Wayland windows.